Effect of the Surface Layer Formed by Laser Oxidation on Fracture Mechanics of Titanium Alloys

摘要

For many practical applications of coated parts the effect of surface layers on the material properties is the main factor when selecting a strengthening method. It has been revealed that low-cycle loading fracture is initiated in the subsurface zone lying below a strengthened layer. Such behaviour of materials is due to the difference in the surface layer and the base metal properties and the complex form of residual stresses detected in the base along the surface layer boundary and in the surface layer itself. Tests have brought out that under low cycle loading conditions the number of cycles to failure in titanium specimens strengthened by laser oxidation increases up to 100000 with a loading of 0.8 of the base metal.